WO 98/42986 A1 discloses a fluid cooling device as a modular unit with a motor which drives a fan wheel and a fluid pump which takes fluid from an oil tank and delivers it to a hydraulic working circuit which heats the fluid. The fluid pump routes the fluid to a heat exchanger (cooling unit). From the heat exchanger the cooled fluid is returned to the oil tank. The oil tank is made trough-shaped and with raised trough edges partially encompassing at least the motor and the fluid pump in the shape of a half shell. With the known solution, the actual modular unit of a filter unit, a pump unit and a cooling unit can be connected in a space-saving manner to a relatively high-volume oil tank as the tank unit. From the installation space left free by the trough edges of the oil tank, good accessibility of the remaining modular unit is ensured for mounting and maintenance purposes. The known fluid cooling device for the most part avoids additional tubing. Avoiding additional tubing helps save costs and is energy-efficient, because losses in the fluid lines are avoided. Regardless, the known fluid cooling device can be sold only as an integral modular unit of the combination of filter unit, pump unit, cooling unit and tank unit. In particular, retrofitting onto existing oil tanks or tank units with the further modular unit is hardly possible. Since these tank units and oil tank units often originate from other manufacturers and are already on site, depending on the respective application it would be desirable to retrofit these units with a modular unit of a filter unit, a pump unit and a cooling unit as required, or if necessary to undertake modifications such that one fluid cooling device is replaced by a new one, for example, with greater capacity. In this connection, the respective tank unit remains on site.
Accordingly, the prior art (WO 01/18363 A1) discloses connecting fluid cooling devices as modular units to oil tanks or tank units provided separately from them. The known solution relates to a fluid cooling device with a cooling means, filter means, and pump means combined into a modular unit. The fluid conveyed in the fluid circuit by the pump means is filterable by the filter means and coolable by the cooling means. The filter means has at least one filter element which can be replaced when it is fouled. In that in the known solution for the replacement of the respective filter element in the fluid circuit, an actuatable blocking means is present with which the filter means can be separated from the pump means such that the cooling means is further supplied with the fluid to be cooled. It is possible in the known solution to enable the filter element replacement without additional effort even if the downstream lubricating oil supply is not shut off. The known fluid cooling device can be connected as a modular unit, depending on its capacity, to any oil tanks or tank units. For this purpose, the corresponding tubing or fluid-carrying lines, between the modular unit and the tank unit are necessary. As already explained, this tubing is associated with the corresponding complexity in terms of production and installation. This tubing also raises costs, and flow resistances arise due to the length of the fluid lines provided between the modular unit and the tank unit. This arrangement has adverse effects on the energy-efficient operation of the means as a whole. The additional fluid lines also result in increased installation space. In applications in automotive and mechanical engineering and apparatus engineering, this arrangement often leads to problems, where often there is only little installation space due to given boundary conditions.